In general, police racism/excesses do exist and yes really stupid (or worse) behavior by minorities really exist. One of the greatest fallacies is to identify one party that has fault in a matter and then stop looking.
Concerning Professor Crowely, well I think he's probably an enlisted jerk that allowed his veiled prejudices to show.
The secret is knowing how much (or even if) one of these elements is involved in each particular incident and not allowing baseless to accusations deflect real fault. One of the greatest fallacies is to identify one party that has fault in a matter and then stop looking.
What good does showing the police his Harvard ID. I doubt it has his home address on the ID. He was just trying to show the police how important he is.
Small correction. Gates is the professor, Crowley is the police officer.